We randomly assigned 4589 healthy nulliparous women who were 13 to 21 weeks pregnant to receive daily treatment with either 2g of elemental calcium or placebo for the remainder of their pregnancies. Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset. Additional analyses utilizing the study database and specimen repository are being performed. During FY06 papers were published on the relationship of midtrimester blood pressure in women who subsequently developed preeclampsia to the concentration of sFlt1 after onset of clinical signs and on soluble endoglin and other circulating antiangiogenic factors in preeclampsia. Work on angiogenic factors and preeclampsia is continuing.